The present invention relates generally to a watthour demand meter and more particularly to a cover (housing) mounted meter register reset actuator incorporating a tamper resistant security lock and meter register access assembly.
Watthour demand meters are well known in the prior art. A common type of demand meter currently in use by the electric utility industry is a conventional watthour meter mechanism, used in combination with a timing element, to sum up the kilowatt hours of energy measured by the watthour meter in a pre-selected time span called a demand interval. Usually a demand interval of 15 or 30 minutes is selected for such meters. In order to indicate the maximum power demand on a customer's system in a given billing period, such as during a one month span, an indicating mechanism, such as a demand register indicator, is incorporated in all demand meters. At the end of the billing period the demand register is generally read by a utility company employee. After the register has been read, the register is reset back to zero. Thus, the indicator, as it moves up scale, registers the amount of peak power consumed during any demand interval in the subsequent billing period.
There are various types of meters having demand registers, the majority of which are either mechanical or electromechanical. However, one known type of meter which registers peak and demand power consumption has electronically programmable logic for controlling the operation of the peak and demand registers in that meter. Such a meter is described in U.S. patent application Ser. No. 881,503, filed on Feb. 27, 1978, entitled "TIME OF DAY DEMAND METERING SYSTEM AND METHOD", and U.S. Pat. No. 4,050,020, both assigned to the assignee of the present invention. In this type of meter it is desirable to be able to reset the demand register electronics from outside the meter, as well as being able to gain access to the meter electronics through the meter housing to program the electronic logic without physically removing the meter housing.
To accomplish the aforementioned register reset and programming functions, a need exists for a combination register reset and access assembly which can be securely locked to prevent unauthorized access or meter tampering and which, when locked, seals the register housing to prevent register contamination caused by external elements, such as blowing dust, rain and the like.